Vibration isolation members are frequently used in aircraft interior applications to reduce the vibration and noise exposure to delicate and sensitive instrumentation and also to passengers in the aircraft cabin. In aircraft applications the vibration isolation members must provide the requisite vibration reduction with a minimum size and weight vibration isolation member.
One means for effectively reducing such exposure to noise and vibration is to use a vibration isolation member that has iso-elastic stiffness properties. A vibration member that is iso-elastic has equal stiffness in the axial and radial directions. Iso-elastic stiffness permits the vibration isolator to provide dependable performance in any orientation and maximize vibration reduction for a given installation. A vibration isolation member that does not provide such iso-elastic stiffness properties will transmit vibration more efficiently in one or more directions, compared to an iso-elastic vibration member having the same minimum stiffness.
Additionally, it is desirable to include a mount fail-safe feature that prevents the mount from separating in the event the mount fails under loading. Several prior art mounts provide fail safe features that function in a single axial direction however, such prior art mounts typically do not have two fail safe paths. Moreover, in vibration isolation members that comprise iso-elastic members, the members frequently do not have a fail-safe or interference path that is defined by the components that comprise the mount. Rather the fail-safe feature is produced by adding washers or other discrete mechanical members to the member. The additional components required to provide a fail safe feature in an iso-elastic vibration isolation member add weight and increase the volume required to house the member in the aircraft.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide a vibration isolator that provides iso-elastic stiffness in combination with fail safe feature and thereby solves one or more of the shortcomings of present isolation devices and methods. Accordingly, a suitable vibration isolation member is provided including features more fully disclosed hereinafter.